linux-kernel - Re: [PATCH] power: supply: da9150: use div64_u64() instead of do

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Message-ID: <20220211205026.6jhtt66wco5ht6i6@mercury.elektranox.org>
Date:   Fri, 11 Feb 2022 21:50:26 +0100
From:   Sebastian Reichel <sebastian.reichel@...labora.com>
To:     Qing Wang <wangqing@...o.com>
Cc:     Support Opensource <support.opensource@...semi.com>,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] power: supply: da9150: use div64_u64() instead of
 do_div()

Hi,

On Wed, Feb 09, 2022 at 12:39:46AM -0800, Qing Wang wrote:
> From: Wang Qing <wangqing@...o.com>
> 
> do_div() does a 64-by-32 division.
> When the divisor is u64, do_div() truncates it to 32 bits, this means it
> can test non-zero and be truncated to zero for division.
> 
> fix do_div.cocci warning:
> do_div() does a 64-by-32 division, please consider using div64_u64 instead.
> 
> Signed-off-by: Wang Qing <wangqing@...o.com>
> ---

Thanks, queued.

-- Sebastian

>  drivers/power/supply/da9150-fg.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/power/supply/da9150-fg.c b/drivers/power/supply/da9150-fg.c
> index 6e36782..896491a
> --- a/drivers/power/supply/da9150-fg.c
> +++ b/drivers/power/supply/da9150-fg.c
> @@ -250,7 +250,7 @@ static int da9150_fg_current_avg(struct da9150_fg *fg,
>  	div = (u64) (sd_gain * shunt_val * 65536ULL);
>  	do_div(div, 1000000);
>  	res = (u64) (iavg * 1000000ULL);
> -	do_div(res, div);
> +	div64_u64(res, div);
>  
>  	val->intval = (int) res;
>  
> -- 
> 2.7.4
> 

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